"Captain's log, stardate 3417.3. We thought our mission to Omicron Ceti III would be an unhappy one. We had expected to find no survivors of the agricultural colony there. Apparently, our information was incorrect."

Sandoval and two other colonists are excited to see others than themselves; they haven't seen other Human beings since they left Earth. Sandoval explains that the colony's subspaceradio had malfunctioned and they did not have anyone with the expertise capable of repairing it. Kirk grimly notes that they did not come here because the radio was broken but Sandoval says they are glad the Enterprise crew are here nevertheless. He offers to show the colony to them. "On pure speculation, just an educated guess – I'd say that man is alive", McCoy tells Kirk. Spock notes that the berthold rays are deadly to all life on this planet – the colonists should be dead. The crew of the Enterprise would be safe on Omicron Ceti III for a week but not for four years, as the colonists have. As McCoy and Spock debate how the colony's inhabitants could possibly still be alive, Kirk tells the landing party that they had better find some answers first.

In a house, Spock encounters Leila Kalomi, a botanist he had met on Earth six years prior. She had loved him, but he had been unable to return her love despite being half-Human. Sandoval tells Kirk, McCoy, and Spock that the colony's philosophy is that man should return to a life less complicated by machinery. Thus, the colony has no mechanical devices or vehicles and weapons. "We have harmony here – complete peace", Sandoval proudly says. Elsewhere, anomalies in the colony are discovered by Sulu and Kelowitz, such as the total lack of any animal life on the colony, like cows, pigs, horses, and dogs.

Alone together, Leila promises Sandoval to tell Spock their secret. Sandoval asks Leila if he would like Spock to stay with them and live as they do. "There is no choice, Elias. He will stay." Later, during his examination of the colonists, McCoy is astounded to discover that every inhabitant is in perfect physical health, even to the point where childhood injuries have repaired themselves. He points to the example of Sandoval's multiple health problems prior to journeying to the planet, such as scar tissue found on his lungs that cannot be detected now or his removed appendix, which is somehow back in his body. Sometime later, Kirk tells Sandoval that Starfleet Command has just ordered him to remove the colonists from the planet but Sandoval tells Captain Kirk that they will not leave. Kirk says this is not an arbitrary decision on his part but Sandoval still says they are not leaving, "it's entirely unnecessary", he says. McCoy reminds Sandoval of the deadly berthold rays currently bombarding the planet and their effect but Sandoval tells the doctor of their healthy lifestyle that is a plant based diet and that no colonist has of yet died. Kirk asks him how their animals have died and the colonists have not. Sandoval dodges the question and still refuses the captain's order to leave.

Outside, Leila leads Spock towards a flowering plant, she says she was one of the first to find them. Spock is then blasted with spores. The spores cause Spock's emotional barriers to break down, making him drop his tricorder and react in physical pain, which quickly passes. He gets back up in a euphoric state and confesses his love for Leila, who says the Vulcan is now one of them. They kiss passionately.

"Captain's log, supplemental. We have been ordered by Starfleet Command to evacuate the colony on Omicron III. However, the colony leader, Elias Sandoval, has refused all cooperation and will not listen to any arguments."

When Kirk hails Spock with his communicator, his first officer responds casually and lacking any respect or formality for his commanding officer. McCoy notes that this behavior didn't seem like Spock at all. Kirk attempts to question Spock further, but Spock drops the communicator and again directs his attention to Leila. Concerned, Kirk follows the open com link, and finds Spock laughing and clowning around – actually hanging from a tree. When Kirk orders Spock to be placed under arrest, the Vulcan leads Kirk and his officers a short distance, stopping in front of one of the spore plants. Immediately, the spores blast Sulu and Kelowitz, who both exhibit the same euphoric behavior of the people on the planet. Meanwhile, DeSalle, already under their influence as well, infects Dr. McCoy, who begins beaming the plants aboard the Enterprise.

Kirk decides to go back to the Enterprise. However, because Dr. McCoy had ordered about a hundred plants beamed aboard, the spores are carried throughout the Enterprise by the ship's ventilation system. He orders Lieutenant Uhura to contact Admiral James Komack at Starfleet. Lieutenant Uhura, under the spores' influence herself, leaves the bridge to beam down, but not before completely sabotaging the communications station. Only short-range sensors, to be able to contact the crew on the planet, remain. In a fit of rage, Kirk throws one of the pod plants on the bridge over the helm console and storms out. Outside the transporter room, the captain discovers that his entire crew is beaming down to the surface and orders them to go back to their stations. Leslie, speaking for the deserting crew, refuses and openly admits his actions are mutiny against the captain.

"Captain's log, stardate 3417.5. The pod plants have spread spores throughout the ship, carried by the ventilation system. Under their influence, my crew is deserting to join the Omicron colony and I can't stop them. I don't know why I have not been infected nor can I get Dr. McCoy to explain the physical-psychological aspects of the infection."

Kirk returns to the planet to find McCoy, to the house where he finds Spock and Sandoval. Spock responds by saying McCoy went to "make something called a mint julep." He goes on to explain the spores not only induce a feeling of total peace and euphoria, but they are also the reason that the colonists have been protected from the deadly berthold rays. Spock, able to act as a scientist notwithstanding still being under the influence of the spores, explains that the plants traveled through space until they landed on the planet, actually thriving on the berthold rays. The plants act as a repository for thousands of microscopic spores until they find a Human body to inhabit. In return, they give their host complete health and peace of mind: in short, paradise; "It's a true Eden, Jim." When Kirk hears that, he disagrees, stating that Humans weren't meant for that. He insists that man stagnates if he has no challenge to drive him and motivate him. But Spock says that Kirk simply doesn't understand now, but that he will come around eventually and really comprehend what they mean and join them.

"Captain's log, stardate 3417.7. Except for myself, all crew personnel have transported to the surface of the planet. Mutinied. Lieutenant Uhura has effectively sabotaged the communications station. I can only contact the surface of the planet. The ship can be maintained in orbit for several months, but even with automatic controls, I cannot pilot her alone. In effect, I am marooned here. I'm beginning to realize just how big this ship really is, how quiet. I don't know how to get my crew back, how to counteract the effects of the spores. I don't know what I can offer against paradise."

The bridge is deserted, save for the quiet beeping of the various stations running on automatic. Kirk enters and surveys his situation. He tries to call Scott in engineering, but receives no answer. Other sections of the ship are similarly deserted. Recording his log, he notes that while the Enterprise can remain in orbit for several months without a crew, he cannot pilot the ship alone, even with automatic controls. He realizes that he's ultimately been marooned aboard the Enterprise. Moving over to the helm station, Kirk laments on how big and quiet the Enterprise is without anyone aboard and wonders how he can possibly get his crew back; what he can possibly offer, he rhetorically asks himself, against the paradise that the spores bring. Lost in thought, he forgets that he is sitting near the pod plant he threw earlier when it blasts him with a dose of the spores. He becomes just as mindlessly happy as the others and hails Spock to let him know that he finally understands and wants to join them after all. Returning to his quarters to pack, Kirk opens his safe and finds one of his medals. A look of frustration comes over his face and he refuses to take the medal with him. He angrily closes the box and immediately leaves his quarters. About to beam down to the planet, he suddenly gets hold of himself and becomes angry, yelling that he cannot leave the Enterprise, and, after slamming his fist down on the transporter console, he becomes himself again, free of the spores. He realizes that violent emotions and anger are what counteract the spores' euphoria-inducing effects. Noting this cure for the spores in his log, Kirk also realizes that his plan to free his crew and the colonists from the spores' effects and escape Omicron Ceti III comes with one potential danger: Spock. Knowing his first officer to be considerably stronger than a normal Human being and could kill him with his bare hands, Kirk decides to risk it.

"Captain's log, supplemental. I think I've discovered the answer, but to carry out my plan entails considerable risk. Mr. Spock is much stronger than the ordinary human being. Aroused, his great physical strength could kill. But it's a risk I'll have to take."

Kirk, pretending to still be under the influence of the spores, hails Spock and tells him that he would like some help in moving some of the ship's equipment that could be useful down on the planet. Spock offers to send a team, but Kirk says he thinks the two of them can handle it. Spock agrees and beams up, telling Leila he will return soon. However, upon returning to the ship, Spock is greeted with Kirk threateningly brandishing a metal pipe and calling him a "mutinous, disloyal, computerized, half-breed." Spock thinks Kirk is joking, but, the captain persists and begins insulting Spock's parents and the entire Vulcan race. Spock pleads with Kirk to stop, but, he continues, now turning his attention to Leila and how Spock couldn't possibly love her, and that he is a freak who belongs in a circus, "right next to the dog-faced boy." At this, Spock finally snaps and attacks Kirk, throwing him around the transporter room.

As he prepares to smash a small metal table over Kirk's head, Spock regains control of himself and is broken from the spores' influence. He and Kirk set out to create a subsonic transmitter that will induce anger and intense emotions in everyone on the planet's surface via the crew's communicators, thus eradicating the spores.

Enterprise officers shaking off the effect of the spores

When Leila beams up to the ship to find out what happened to Spock, she tells him that she cannot lose him again. But Spock tells her that he has a responsibility to the ship, and to his friend the captain. He goes on to tell her that he is who he is, and that if there are self-made purgatories then we all have to live in them, that his can be no worse than that of someone else. Leila cries and then realizes that she lost not only Spock but the feeling the spores induced as well. However, she says that her feelings for Spock still have not changed and that she still loves him.

The transmitter is activated, and fights break out across the colony, destroying the spores' effects. Sandoval expresses regret, noting that they have not really accomplished anything in three years, as any progress they made was purely the result of the spores. He hopes that he and the other colonists can try again on another planet. As the Enterprise leaves Omicron Ceti III for Starbase 27, McCoy cynically states that this is the second time Humans have been thrown out of paradise and Kirk responds jokingly that actually this time they just walked out on their own; maybe they weren't meant for paradise, says Kirk, maybe they were meant to fight their way through, struggle and scratch for every inch of the way. Spock, on the other hand, realizes that his time with Leila on the surface was the first time he had ever been happy.

"What makes you think you're a man? You're an overgrown jackrabbit; an elf with a hyperactive thyroid!"

- Kirk, provoking Spock into a fight

"What can you expect from a simpering, devil-eared freak, whose father was a computer and his mother an encyclopedia?"

- Kirk, provoking Spock into a fight

"Your father was a computer, like his son! An ambassador from a planet of traitors! The Vulcan never lived who had an ounce of integrity!"

- Kirk, provoking Spock into a fight

"You're a traitor from a race of traitors! Disloyal to the core! Rotten...like the rest of your subhuman race! And you've got the gall to make love to that girl!"

- Kirk, provoking Spock into a fight

"Does she know what she's getting, Spock? A carcass full of memory banks who should be squatting on a mushroom instead of passing himself off as a man! You belong in a circus, Spock, not a starship! Right next to the dog-faced boy!"

- Kirk, before Spock strikes him

"It isn't every first officer who gets to belt his captain... several times."

- Kirk, after Spock is cured

"I am what I am, Leila. And if there are self-made purgatories, then we all have to live in them. Mine can be no worse than someone else's."

- Spock to Leila, in the transporter room

"You never told me if you had another name, Mister Spock."
"You couldn't pronounce it."

- Leila and Spock, as he wipes away her tears

"We don't need you. Not as a doctor."
"Oh, no? Would you like to see how fast I can put you in a hospital?"

- Sandoval and McCoy, before McCoy punches him

"You better make me a mechanic, then I can treat little tin gods like you!"

- McCoy, getting angry at Sandoval

"I have little to say about it, captain. Except that for the first time in my life, I was happy."

- Spock, about Omicron Ceti III

"Well, that's the second time man's been thrown out of Paradise."
"No, no, Bones, this time we walked out on our own. Maybe we weren't meant for paradise. Maybe we were meant to fight our way through, struggle, claw our way up, scratch for every inch of the way. Maybe we can't stroll to the music of the lute. We must march to the sound of drums."

In Jerry Sohl's original draft (first titled "Power Play," then "The Way of The Spores"), it was Lieutenant Sulu who was infected by the spores and was able to fall in love with the Eurasian beauty Leila. McCoy discovered an internal condition that would have necessitated Sulu's resignation from Starfleet service, had the spores not cured his condition. His illness gave Sulu a will to develop a relationship with Leila just as similar circumstances would later affect McCoy's judgment in "For the World is Hollow and I Have Touched the Sky". (The Star Trek Compendium, p. 59)

The spores, in the early drafts, were a communal intelligence; when someone was possessed by them, that individual was granted telepathic abilities to link up with other possessed minds. The abilities of the spores to restore health were complete enough to enable them to return the dead to life. The antidotes for the spores were either the possession of a certain blood type or the introduction of alcohol into the affected person. Originally, Kirk leaped onto Spock and forced liquor down his throat to restore him to normal. In a surprise ending, the spores were revealed to be benevolent, conscious entities who never intended to act against anyone's will. (The Star Trek Compendium, p. 59)

According to Dorothy Fontana, the episode had to be seriously rewritten because Sohl had not quite gotten it right. Gene Roddenberry told her, "If you can rewrite this script, you can be my story editor." She thought about it and eventually realized that the story wasn't really about Sulu, but about Mr. Spock. Nimoy, who was initially taken aback when he was told that they were working on a love story for Spock, later felt that the episode turned out to be a lovely story. (TOS Season 1 DVD feature Kiss 'n' Tell: Romance in the 23rd Century)

One of the basic aspects that Fontana immediately changed was Sohl's original conception of the spore plants residing in a cave. Thus, to avoid the danger of the plants, the crew merely had to avoid the cave. Fontana put the plants everywhere around the planet, and later the Enterprise to make them a real menace. (Star Trek: The Original Series 365, p. 131)

Jerry Sohl was unhappy with Fontana's rewrites of his script and credited himself under his pseudonym "Nathan Butler". [1]

The script featured characters named Lieutenant Timothy Fletcher and Crewman Dimont as members of the landing party. When Michael Barrier and Grant Woods were cast in these roles, the names were changed to DeSalle and Kelowitz respectively, to appear constant with the two actors' previous appearances on the series. [2]

In writing up the episode for Star Trek 5, James Blish added a response from Spock after Leila tells him, "It's been a long time": "The years have seemed twice as long." Blish also depicts Spock awkwardly taking her hand.

Originally "The Devil in the Dark" was scheduled to be filmed before this episode with Ralph Senensky directing it, and Joseph Pevney directing "This Side of Paradise", but during pre-production the two episodes were switched, and changed directors. It was due to producer Gene Coon's assumption that "Devil" would be a tough assignment for a first-time Trek director. [3][4]

In a blooper, Leonard Nimoy flubs his line about the plants acting as a repository for thousands of spores. Instead, he says the plants act as a "suppository." The crew cracks up, as does Nimoy, who caps the fun by putting a Tootsie Pop in his mouth. [5]

The empty shot of the bridge, before the turbolift opens to admit Kirk, was the best available piece of film for TNG: "Relics" to reuse as the holosimulation of the NCC-1701 bridge. The short snippet of film was "looped" several times and bluescreened in behind James Doohan and Patrick Stewart's scenes. Using the stock footage in this way eliminated the need to completely rebuild the bridge – they only built a short section of the computer stations, the door alcove, and the command stations for the TNG-era actors to sit at.

The large open meadow seen in several sequences is in Malibu State Park in southern California. It is the same spot where the hunt in the corn field took place in Planet of the Apes, and also extensively used in the series Gunsmoke. (citation needed • edit)

The barn Kelowitz and Sulu investigate can be seen in several episodes of Kung Fu. (citation needed • edit)

The buildings seen in the teaser, the first scene after and the scene in which DeSalle shows McCoy the Spores are at a different location than the buildings seen in the rest of the episode. The green farm structures were located at the Disney Ranch. The concept of Sandoval's people refusing modern technology was intended to justify the late-19th century American style of the ranch. [8]

According to director Ralph Senensky, the original schedule was that the first three of the six shooting days were to be spent on location, shooting at the Golden Oak Ranch (also known as the Disney Ranch), then the remaining three days indoors, filming the Enterprise scenes. However, after two days of shooting outdoors, Jill Ireland fell ill and couldn't appear on the set. It was in question if she had measles or not. Senensky decided to film all the farm scenes which didn't contain Leila's character and then return to the studio for Enterprise interiors in the remaining of the day, and hope for the actress' return. Ireland appeared the following day, as it turned out that she did not have measles. However, the crew couldn't return to Disney Ranch as it was already booked for another production. They decided to film the remaining scenes at Bronson Canyon. [9]

Spock and Leila in a deleted scene

In the script, Kirk first spots Spock and Leila kissing passionately by the stream; there is no scene of Spock hanging off the tree limb. That facet of the episode may have been made up on the spot. [10] Indeed, director Ralph Senensky came up with the idea of Spock hanging from the tree on location, when he found the tree and the spot closely to Bronson Canyon. Originally the scene was to be shot on a clearing. [11] Evidence taken from a deleted scene, of Spock and Leila's presence near the stream, appears in the episode's preview trailer.

The food processors in the transporter room, placed there so Kyle could provide chicken soup for the air sergeant in "Tomorrow is Yesterday", disappeared from the room by the end of the first season. In this episode, an enraged Spock destroys one of them.

There is a piece of equipment attached to the left side of the transporter console. It seems to serve no purpose, other than for Spock to hit when he misses Kirk during their brief dust-up, and was only seen in this episode. In fact, it was not in the scene where six crew members, under the influence of the spores, transport down.

Similarly, the tray-like metal object that Spock is poised to throw on Kirk at the end of Act III is not seen in the transporter room in any other episode.

The suitcase in which Kirk packs his belongings, and which he later places on the transporter platform, is a very obvious piece of 20th century Samsonite luggage.

In "The Tholian Web", Chekov asks Spock if there has ever been a mutiny on a starship before. Spock replies that there has never been, despite the fact the events of this episode were specifically called a mutiny.

Although DeSalle wears a gold uniform top denoting that he is a member of the command division, it is he who is assigned to deliver a biology report on the colony. A more logical choice would have been Kelowitz, a blue-shirted member of the sciences division.

In this episode, McCoy atypically hangs his tricorder on his right shoulder without the strap crossing his torso so that the instrument will dangle at his left hip.

At one point during his log recording, Kirk refers incorrectly to the planet as "Omicron III."

Although Kirk hurls the pod plant across the bridge before storming out after Uhura abandons her post and it is that same plant that subsequently infects Kirk when he's sitting at the helm console, when the empty bridge is seen when Kirk records his log entry, the pod plant is nowhere to be found.

Dorothy Fontana very much liked the finished episode. She recalled, "It worked out very well because the actors were brilliant for me, and had a very good director, and you know, I really like it."[12]

Ralph Senensky recalled that directing the episode "really proved to be very, very, very well worthwhile doing. Leonard [Nimoy] and Jill [Ireland] were wonderful, as was the whole cast." [13]